Asphalt pelletizer



July 24, 1951 G. B. MoLLRlNG 2,562,149

ASPHALT PELLETIZER Filed April 17, 1947 Patented July 24, 1951 ASPHALT PELLETIZER Gilman B. Mollring, Los Angeles, Calif. Application April 17, 1947, Serial No. 742,149

` (ci. 12s- 2.4)

7 Claims.

This invention relates to an apparatus for 'transmuting a hot liquid asphalt into a multiplicity of tiny, cold, solid pellet-like particles of asphalt which are coated With a pulverulent material to inhibit coalescence.

Solid asphalt is both diicult and` expensive to package and handle, since it is usually sold in woodenbarrels, steel drums, clay lined paper bags or hexagonal cartons, etc. therefore to provide some means whereby asphalt may be handled either in bulk or returnable containers.

It is van object of this invention to supply an apparatus whereby solid asphalt may be divided into small particles or pellets which are coated with a pulverulent materiali, and thereby become stable to storage and susceptible of convenient handling. v

Brieiiy, the invention comprises a substantially horizontal moving belt upon which a bed of -the pulverulent coating material is deposited, and means forspringling the molten asphalt on the' moving bed of coating material so thaty it ybecomes divided into particles which are coated -with the powdered material, and is also cooled by the coating material.

The lcoated pellets are then separated from the excess powdered coating material, and the latter is cooled and recycled. y

The invention may be best understood by reference` to the attached drawing, which illustrates a suitable form of apparatus.l l

Referring to the drawing, the powdered coat- .ingmateriaL which in this example will be referred to as clay, is stored in bin I from which it is elevated by elevator 2 to cooler 3 which may be equipped with ventilators 3a or other means ,for indirect cooling of the clay. rIhe cooled clay is fed at a uniform rate by means of feeder lA to spreader 5, which may be a shaker or any while warm and sticky, and are cooled by conl tact with the excess clay during the succeeding conveyance on belt '6. From belt 6 the pelletclay mixture is dropped through inclined screen 8 which serves to separate the pellets and provide a means for their withdrawal. The excess It is desirable clay passes through screen 8 and funnel 9 onto return conveyor I which serves to return it to bin I for recycling through the apparatus as above described. Fresh clay and asphalt are added to bin l and heater 1w as required. The

vapparatus may be enclosed to protect. the operator from dust if desired.

In a specific` example of the apparatusl described a belt 6 was employed which was approximately linches wide and thirty feet long beyond the point of addition of the asphalt. The belt was moving at a rate of about 10 feet per second, andv Was covered with a substantially uniformfbed of powdered mica which was added thereto at a rate of about 500 pounds per minute. The asphalt, which was an air blown asp-halt of about 250 F., (R & B) Was heated to a temperature of about 350 F. and-sprayed under nitro-gen pressure through a ian shaped nozzle, at a rate of about pounds per minute. The nozzle opening was about inches wide and about 2 inches long at its outerend,v and was tapered at about 35 angle to provide va fan shaped spray. lThe nozzle opening was about 20 inches above the conveyor4 belt.

It was found that in an apparatus of the above type, pellets of asphalt of aboutlO mesh could be produced, which were coated with powdered mica for example, the coating material amounting to approximately 10% of the vr'weight of the asphalt. The coated pellets were'readily stored and very easily handled.

It is to be understood, of course, that many variations may be made in the above specific example oi the apparatus. IIhe elevator maybe any means for elevating the clay, as for example a continuous conveyor of the bucket type, or a gas lift or pneumatic conveyor. The cooler may be any type suitable for cooling the solid powdered clay. If a gas lift elevator system ernployed, the cooling and gas lift may be accomplished simultaneously by employing a cool gas in the lifting operation. The heating of the asphalt should be sufficient to melt it and reduce its viscosity sufficiently so that it may be' separated into one or more ne streams by ynozzle l. Preferably, nozzle 1 should be far lenough from belt 6 so that `the fine stream breaks-up into droplets before striking the bed of clay,^although it has been found that the apparatus will serve to break the stream up into pellets even after it has reached the clay bed. The clay should, of course, be in a' suicient excess to cover the entire pellet and also provide a further bed as a cushion and a cooling means.

The length of belt 6 beyond a point at which the asphalt is applied should be suicient to provide cooling of the coated pellets by the excess clay to a temperature below its melting point or to an extent suiicient to prevent agglomeration of the pellets on screen 8. Screen 8, of course, may be substituted by a classifier or elutriator or other means of separating the coated pellets from the residual clay. The latter may be returned to bin l by any suitable conveyor means.

Although clay and mica were employed as the coating materials in the above description, any suitable coating material may be employed. Preferably the material is powdered, i. e., divided into particles not greater than approximately 100 mesh in size. The coating material may consist in whole or part of clay, ground mica, lime, talc, or similar mineral materials or it may consist in whole or part of powdered gilsonite, natural rock asphalt or similar material having a general thermoplastic nature of a relativelyY high melting point.

The asphalt to be pelletized may be any asphalt which is solid at room temperatures, such as air blown asp-halts or steam refined asphalts.

Modifications of this invention which would occur to one skilled in the art may be employed and these are to be included in the scope of the invention as defined in the following claims.

I claim:

l. An apparatus for forming pellets of asphalt which are coated with a coating material, which comprises a substantially horizontal moving belt, means for applying a substantially uniform.

bed of powdered coating material thereon, means for sprinkling molten asphalt on sai-d bed of coating material, solids separator means for separating the resulting coated pellets from the excess coating material, solids coolerl means andrg;

solids conveyor means for recycling the cooled separated coating material to said moving belt.

2. An apparatus according to claim l inv which the length of the bel-t 'beyond the point of addition of the asphalt .is suicient to provide cooling ,n

nozzle capable of delivering afan-shaped stream ,jv

toward themoving belt.

5. An apparatus for forming pellets of asphalt which are coated with a coating material so as to prevent agglomeration thereof, which comprises a storage bin for powdered coating material, an elevator adapted to elevate the coating material from the storagebin, a cooler adapted to receive lcoatingmaterial from the upper portion of the elevator and cool it while allowing it to pass continuously downward by gravity therethrough, a feeder attached to the lower portion of said cooler adapted to regulate the flow of coating material therethrough, a shaker for receiving coating material discharged from the feeder and spreading a uniform bed of said coating material, a horizontal conveyor belt adapted to receive said bed of coating material, a spray nozzle adapted to sprinkle molten asphalt on said bed of coating material, an inclined screen adapted to receive the mixture of pelleted asphalt and excess coating material discharged from the conveyorv belt and separate the pelleted asphalt therefrom, and conveyor belt means for reconveying the excess coating material to said storage bin.

6. An apparatus for forming pellets of asphalt which are coated with a powdered coating material of smaller than 100 mesh size, which comprises solids cooler means for cooling said coating material, a horizontal conveyor belt means for withdrawing cooled coating material from said cooler and depositing the cooled coating material in a bed of uniform thickness on said belt, a spray nozzle adapted to springle molten asphalt on said bed of coating material, said spray nozzle being located sufficiently far above said belt so .that the molten asphalt breaks up intov droplets before striking said bed, said bed being suflicient- 1y deep to cover said droplets completely, cool them to form sticky pellets and provide a cushion therefor, andsaid'belt being suiciently long beyond the point at which the asphalt is applied to provide cooling of the coated pellets to a temperature suiicient to prevent agglomeration thereof, solids separator means for separating. the coated pellets from the excess coating material, and solids conveyor means for recirculating the excess coating material to said solids cooler means.

7. An apparatus for forming pellets of asphalt which are coated with a .powdered coating material of smaller thanlOO mesh size, which comprises a substantially horizontal conveyor belt adapted to carry thereon a bed of saidcoating material, nozzle means for embedding droplets of hot molten asphalt in said bed, solids cooler means and solids distributor means for maintaining said bed sufciently co-ol and sufficiently deep to cover said droplets completely, cool them to form sticky pellets, and provide a cushion therefor, solids separator means forY separating the resulting coated pellets from the excess coating material, and solids conveyor means lfor recycling the excess coating material to said solids cooler means.

GILMAN B. MOLLRING.

REFERENCES CITED The following references areA of record in the ille of this :patent:

UNITED STATES PATENTS Number Name Date 1,157,935 Gray Oct. 26, 1915 1,792,805 Broderick Feb. 17, 1931 1,998,055 McBurney et al Apr. 16, 1935 2,265,303 Moss Dec. 9, 1941 2,294,523 ,Veazey Sept. 1, 1942 2,311,389 Hawks et al. Feb. 16, 1943 2,436,771 Hood Feb. 24, 1948 FOREIGN PATENTS Number Country DateV 284,704 Great Britain Sept. 13, 1928 

